This invention relates to structures that can be used to make connections between tubular medical grafts and a patient""s tubular body conduits. The structures of the invention can alternatively be constructed for use as medical plugs (e.g., to close atrial or ventricular septal defects). The invention also relates to methods for making and using the structures mentioned above.
Tubular grafts are frequently needed in medical procedures. For example, a coronary bypass procedure may involve the installation of a tubular graft between an aperture that has been formed in the side wall of the aorta and an aperture that has been formed in the side wall of a coronary artery downstream from an occlusion or blockage in that artery. Each end of the graft must be connected to the side wall of either the aorta or the coronary artery. Each such connection must extend annularly around the associated end of the graft conduit and be fluid-tight so that no blood will leak out. One common way to produce such connections is by suturing. It will be appreciated, however, that making such connections by suturing can be extremely difficult, time-consuming, and dependent on the skill of the physician for the quality of the results. There is also increasing interest in less invasive procedures which tend to impose constraints on the physician""s access to the sites at which graft connections must be made and thereby make it more difficult or even impossible to use suturing to make such connections (see, for example, Goldsteen et al. U.S. Pat. No. 5,976,178, Sullivan et al. U.S. patent application Ser. No. 08/844,992, filed Apr. 23, 1997, and Sullivan et al. U.S. patent application Ser. No. 08/869,808, filed Jun. 5, 1997, all of which are hereby incorporated by reference herein in their entireties). Various types of mechanical connectors have been developed to reduce or eliminate the need for suturing, but improvements are constantly sought for such mechanical connectors with respect to considerations such as ease and speed of use, ease of manufacture, strength and permanence of the resulting connection, etc.
Plugs are also needed in a variety of medical procedures. For example, it may be necessary to plug an atrial or ventricular septal defect in the heart of a new-born child. Again, improvements are constantly sought for plugs which can be easily and quickly installed using minimally invasive procedures.
In view of the foregoing, it is an object of this invention to provide improved and simplified graft connectors.
It is another object of this invention to provide improved and simplified medical plugs.
It is still another object of this invention to provide improved and simplified methods of making structures that can be used as either medical graft connectors or plugs.
It is yet another object of this invention to provide improved and simplified methods for installing medical graft connectors or plugs.
These and other objects of the invention are accomplished in accordance with the principles of the invention by providing a connector or plug structure preferably formed by starting from a tube of highly elastic material such as nickel and titanium alloy (nitinol) metal. Each end portion of the tube is cut substantially axially at numerous locations spaced circumferentially around the tube to produce a plurality of fingers that extend substantially axially from each end of a remaining medial portion of the tube. The fingers at each end of the medial portion are then deflected so that they extend substantially radially out from the medial portion, and the fingers are set (e.g., by a heat treatment) in that deflected condition. For use of the structure as a graft connector, the medial portion is attached substantially coaxially to an end portion of a graft conduit. For use of the structure as a plug the medial portion of the tube is filled with a suitable plugging material or structure.
To install the graft connector or plug in a patient the fingers at each axial end of the medial portion may be elastically deformed back toward their initial condition (in which the fingers extend substantially axially from the ends of the medial portion). The structure may then be inserted in a delivery tube, which may maintain the fingers in their substantially axially extending condition. The delivery tube may then be inserted through the aperture in the side wall of the patient""s tubular body conduit to which the end of the graft conduit is to be attached, or through the aperture in the patient""s tissue structure that is to be plugged. The delivery conduit may then be removed from around the connector or plug structure. This releases the fingers at each end of the medial portion to spring out on respective opposite sides of the tissue structure to which the connection is to be made, or to which the plug is to be applied.
In some cases fingers may only be formed in one end of a starting tube. A connector may then be provided using two such tubes concentric with one another and with a graft conduit. In such an assembly the fingers on the two tubes extend from generally opposite axial ends of the assembly. Two such tubes may be similarly used to make a plug, although in this case the graft conduit is omitted and the interior of the structure is filled with a plugging material or structure.
As an alternative or addition to use of a delivery tube to releasably hold the fingers substantially parallel to the longitudinal axis of a connector or plug, another structure may be removably placed around the fingers. Examples of such another structure include a collar or a strand of material such as wire or suture material.